Advanced Deep Space Communications Methods

Question: I am seeking recommendations for learning about advanced deep space communication methods. I visited several libraries and found little about how we presently and are preparing for the future of super fast and high speed communication approaches, including encryption, packet integrity, theories on limits and methods, and organizations now involved in developing the technologies.  Please help. Thanks so much.  – Lyndon

Answer: Although it is now a bit dated, the proceedings from a conference on Advanced Methods for Satellite and Deep Space Communications from 1992 might have some useful information on this subject.  Also, the book Satellite Communication Engineering (second edition) might be of use.  These two references are about all I could find on this subject.  Hope this helps.

Jeff Mangum

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What Does an Astronomer Do?

Question: What exactly does an astronomer do? I am 14 and I am planning to become a research astronomer. I would like to know what a research astronomer does… like what does an astronomer trying to find out more about the Big Bang do? Also, how do you know what to do when you first start your job at a University… do a boss or colleagues tell you what to do? Finally, I would like to know some of the most famous Universities for astronomy. Thank you!  – Bethany

Answer: You should check out my Careers in Astronomy page for questions on just this subject that have been answered in the past.  In summary, astronomers are basically physicists that study how the universe works.  Observational astronomers use telescopes to study the properties of things like the Big Bang and interpret those observations, using their knowledge of physics, to help us further understand the properties and evolution of the Big Bang.  Astronomers who specialize in theory use the laws of physics to derived a theoretical understanding of things like the Big Bang which explains it properties and evolution using observations to constrain their theories.  Most astronomers learn “the ropes”, or how to be astronomers, when they are working on their PhD while in graduate school from their research advisor and other faculty and colleagues.  Finally, as for the most “famous” universities for astronomy, there are many.  Different universities with astronomy programs specialize in a wide variety of research areas.  For graduate study one generally chooses a school based on your specific research interests.

Jeff Mangum

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How Far Can a Space Probe Go Before We Lose Contact With It?

Question: Hi, my name is Connor. I’m six years old. I’m doing this for my science fair project. I’m in kindergarten. How far can a probe go before we lose contact with it?

Answer: The only limitation to how far a space probe can travel away from the Earth and still be contacted is its ability to transmit signals to or receive signals from Earth.  For example, the Voyager 1 spacecraft is a little over 2×10^(10) km, or 130 astronomical units, from the Earth and we still receive signals from it.  Eventually we will lose contact with Voyager 1 when its instruments run out of energy to send signals to Earth.

Jeff Mangum

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Did the Big Bang Happen in a Pre-Existing Universe?

Question: Is it possible that the big bang occurred in a pre-existing universe? if not, how do we know?  – Gary

Answer: I think that the best evidence to support the fact that the Big Bang happened in this universe is the fact that we see evidence for its existence in our universe.  There really isn’t any reason to invoke the existence of another universe to explain the Big Bang.

Jeff Mangum

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Could the Accelerating Expansion of the Universe be due to a Pulling Force?

Question: Isn’t it possible that the answer to the increasing speed of the expansion of the Universe is that it is being pulled apart not being pushed apart? If the “unknown” Universe was trillions of light years of dark energy and when the “singularity” appeared, it would have exploded, for lack of a better term, inflation would have occurred, then as gravity was created, the expansion would have slowed down but as the years have gone by the power of all that dark energy, as thin as it is, will eventually overcome the gravity contained in the “known” Universe and pull it into oblivion.  – Philip

Answer: To suggest that the accelerating expansion of the universe is caused by a “pulling” force rather than a “pushing” force would require identifying the source of the “pulling”.  Dark energy is theorized to be a component of the known universe that we had not originally appreciated.  If one wants to incorporate an external force, then one needs to identify from where this force came, which is the difficult part.

Jeff Mangum

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What if the Moon Moved Randomly in its Orbit?

Question: What will happen if the moon moves randomly?  — Ahmed

Answer: Since the Earth’s Moon is an important gravitational influence on the Earth, we would certainly notice if it started to move randomly.  The most noticeable effect of random lunar motion would be unpredictable ocean tides.

Jeff Mangum

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Are UFO’s Real?

Question: What is your opion of UFO’s  observed from ground surface and those observed from space stations and shuttle flights?  I have heard the there is a “Coloney” on the side of the moon we never seen.  Your opinion?  – Kevin

Answer: The fact is that there has never been a confirmed sighting of a UFO that has also been confirmed as evidence of an extraterrestrial presence.  Conspiracy theories are usually based on little or no hard evidence, and are often simply designed to entertain.

Jeff Mangum

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How Difficult is it to get a Job as an Astronomer?

Question: Hi, I am a freshman and I am wondering if it’s hard to get a job as an astronomer because I love everything about space and I am very curious, but I need to know if I will be able to find work?  – Anthony

Answer: Most people who pursue careers in astronomy are able to use the skills they learn in physics, technology, and math in careers in astronomy and related fields.  You might want to look over the careers in astronomy section of this blog for further information on what a career as an astronomer is like.

Jeff Mangum

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When Did the Cas A Supernova Occur?

Question: There is a statement at the following link to the image archive that I do not understand:  The text states that this supernova is 10,000 light years away, but that the supernova event happened 300 years ago. If that were the case, then surely we would not see it for another 9,700 years.  Is the text misleading, or am I misunderstanding something? Thank you.  – Jeremy

Answer: I believe what the text should say is that it is believed that the first light from the supernova reached Earth about 300 years ago, not that the supernova event happened 300 years ago.  As you point out, the supernova event must have happened more than 11,000 years ago in order for light to have reached us.

Jeff Mangum

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What Can Radio Telescopes Measure?

Question: I have some questions about radio astronomy.

  1. If we build a planetary radio telescope, What data can we measure from the received signals other than listening to the noise of S-burst and  L-burst in a project like Radio JOVE?  For example is the calculation of physical phenomena like distance, Temperature, etc possible?
  2. Can we study distant objects like Saturn with a planetary project? Or Magnetic field of Jupiter and Sun?
  3. What are the parameters a radio telescope is capable of gathering? Does it give us intensity-frequency or intensity-angle or something else?

Thank you very much for your time  – Seraj


  1. Radio telescopes can make measurements of the same physical characteristics of planetary objects, such as planets, comets, and asteroids, as do other (optical, infrared, etc.) telescopes.  The difference is that radio telescopes measure different physical phenomena to derive these physical characteristics.
  2. Yes.  Radio observations can, for example, measure the emission from atoms which are spiraling around magnetic field lines in order to measure the strength of those magnetic fields.
  3. Radio telescopes can measure intensity,  position, and polarization as a function of frequency and time.

Jeff Mangum

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